1. There are many different types of time-varying physiological variables that need to be represented in the 3-D space of the brain (e.g. amplitude, polarity, rate of change, phase, coherence with other locations). Each type of physiological variable has different characteristics in terms of the variance it typically manifests over time. Consequently, these variables will need different types of visual (or auditory) representations in the videos in order to maximize their 'visualization'. In addition. visualization of multiple variables from the same data (e.g. amplitude and phase) will often be desirable. Since these variables may have independent temporal variances this will require careful consideration of the coding or mapping of a variable to its visual representation in order to differentiate one variable from another in the video. Finally, many locations will be represented simultaneously (e.g. 10-30 loci), each with time-varying representations. This will require further consid eration of the optimal visualization code for each variable and each location. The first aim of this project will be to optimize representations of the physiological variables for visualization in video. 2. Given the complexity of the data to be appreciated in the videos, additional tools will be needed to optimally visualize the data. Many loci will be active simultaneously in the 3-D space of the brain. The second aim will be to optimize interactive adjustments to transparency, viewing angle, lighting and rotation, independently or simultaneously, and this capability has to be on-line with the video. That is, these adjustments have to be operational while the video is running in order to maximize the visualization of the time-varying representations at each of multiple locations (e.g. superficial and deep). 3. In many cases it will be too difficult to appreciate all the time-varying representations in a data set (e.g. amplitude, polarity, phase. coherence, etc.). The third aim will be to develop methods for rapidly switching between viewing videos of different variables or conditions in an experiment. or toggling! (on-off) which variables are seen during a video. 4. Auditory representations (e.g. time-varying pitch) will be developed to aid in appreciation of the features of the video. For example, different loci in the brain could be assigned different pitches and each of these could vary in intensity. 5. Individual differences are often found and comparisons between individuals will be required. However. comparisons of temporally changing variables at multiple locations in multiple brains simultaneously would be very difficult to appreciate. We propose to utilize the warping parameters provided by the Human Brain Project (A Probabilistic Reference System for the Human Brain) to warp each subject's brain to the common brain and to visualize the data from multiple subjects within this common reference brain. In addition, by making links to this database we will be able to compare the results from ongoing analysis (video) to extant data in the 4-D probabilistic database. and store the resultant 4-D data in the database. This will require development of interfacing with the database and storing these extremely large 4-D data sets. 6. We will fine tune interactive capabilities for creating figures and videos for publication.